Chemical analysis of polycyclic aromatic hydrocarbons and investigation of bioremediation of used railway sleepers

Abstract

Thousands of wooden sleepers have to be change to the new ones every year worldwide. Wooden sleepers impregnated with creosote can be used for about 15 years before they lose their functionality due to strong abiotic factors and microbial activity. According to the regulations of the European Union, any wastes containing polycyclic aromatic hydrocarbons (PAH) can not be used for compost or fuel before treatment and degradation of polycyclic aromatic hydrocarbons in their composition. PAH found in creosote have strong cancerogenic properties. Sixteen of them have also mutagenic properties and are reglamented in EU as the most hazardous and dangerous compounds for human health. One of the ways to degrade PAH is to treat them in high temperature but it is too expensive for such a small country as Lithuania where about 30,000 sleepers are changed annually. Also transportation of ashes to special burning facility in Norway increases expenses. Bioremediation, as a part of the ecological biotechnology, could be successfully applied for hazardous wastes neutralization. Moreover, it is cost effective and environmentally friendly. Bioremediation is based on microorganisms that have ability to degrade selected compounds using their enzymatic properties. The strongest enzymatic properties to degrade PAH containing 3-6 aromatic rings were determined in white-rot fungi species. Downscaled in vitro test was applied for bioremediation screening test.[...]